Aerosol device for dispensing a composition with relatively high viscosity

ABSTRACT

An aerosol device for dispensing a composition with relatively high viscosity, in particular a gel or an emulsion, comprises a can intended to be used with the head upwards, containing the composition and a propellant agent acting directly on the composition. A dispensing valve is in the upper part of the can on an opening of this can, while a dip-tube connected to the valve extends as far as the vicinity of the bottom of the can. The composition (C) to be dispensed has a viscosity (measured on a Brookfield DV III viscometer, needle no. 7) lying in the range of 4000 to 10,000 millipascal.second, preferably of 6000 to 8000 millipascal.second, for a speed of 100 revolutions/minute and of 30,000 to 150,000 millipascal.second, preferably of 50,000 to 120,000 millipascal.second, for a speed of 2.5 revolutions/minute. The dip-tube is a semi-capillary tube (18) whose internal diameter (e) lies between 0.7 and 1.5 mm.

FIELD OF THE INVENTION

The invention relates to an aerosol device for dispensing a compositionwith a relatively high viscosity, in particular a gel or an emulsion, ofthe type of those which comprise a can, intended to be used with thehead upwards, containing the composition and a pressurized gaseouspropellant agent acting directly on the composition, a dispensing valvebeing placed on an opening at the upper part of the can, while adip-tube connected to the valve extends as far as the vicinity of thebottom of the can.

THE KNOWN PRIOR ART

U.S. Pat. No. 3,541,581 shows, in particular in FIG. 5, an aerosoldevice of this kind, in which no physical separation is provided betweenthe pressurized gaseous propellant agent and the composition to bedispensed.

Such an aerosol device is not entirely satisfactory when the viscosityof the composition to be dispensed is relatively high. FR-A-2,223,452emphasizes the difficulties and the problems of operation encountered insuch a situation. The viscous composition does not flow evenly in thedip-tube and cavitation phenomena with loss of propellant gas throughthe dispensing valve occur. This results in a substantial decrease inthe emptying ratio (ratio of the maximum quantity of compositiondispensed by the device to the total mass of this composition introducedinto the can).

In order to overcome such drawbacks, FR-A-2,223,452 proposes stable gelcompositions with retarded foaming having a relatively low flowthreshold, which corresponds to a viscosity which is also relativelylow.

This solution, which rules out more viscous compositions, butnevertheless being of great interest, in particular as regardsself-foaming shaving gels, aims to promote the flow of the compositionin the dip-tube and in the valve in order to reduce the cavitationphenomena.

Such an approach is understandable because it is known that, in order topromote the flow of a product in a set of tubes and pipelines, it isgenerally suitable either to decrease the viscosity of the product whilekeeping the passage cross-sections constant, or to increase the passagecross-sections if the viscosity of the product cannot be altered.

OBJECT OF THE INVENTION

The object of the invention is above all to provide an aerosol device ofthe type previously defined which makes it possible to improve the flowof the composition while avoiding or at the very least while reducingthe cavitation phenomena and while improving the emptying ratio withouthaving to reduce the viscosity of the composition to be dispensed.

SUMMARY OF THE INVENTION

According to the invention, an aerosol device of the type definedpreviously is characterized in that the composition to be dispensed hasa viscosity (measured on a Brookfield DV III viscometer, needle no. 7)lying in the range of 4000 to 10,000 millipascal.second, preferably of6000 to 8000 millipascal.second, for a speed of 100 revolutions/minuteand of 30,000 to 150,000 millipascal.second, preferably of 50,000 to120,000 pascal.second, for a speed of 2.5 revolutions/minute, and inthat the dip-tube consists of a semi-capillary tube whose internaldiameter lies between 0.7 and 1.5 mm and preferably between 1.3 and 1.5mm.

The invention, surprisingly and unexpectedly, makes it possible toimprove the flow conditions of a viscous product, from the point of viewof the evenness of this flow and of the decrease or even the eliminationof cavitation phenomena, by providing a reduced passage cross-section,in contrast to what might be thought.

Tests carried out with an aerosol device according to this embodimenthave made it possible to obtain, in certain cases, an emptying ratio ofmore than 80% during continuous dispensing, and the emptying ratio isimproved in all cases, in comparison with a device equipped with a valveof the same type but with a normal dip-tube whose diameter is greaterthan the values indicated hereinabove, by at least 10% absolute.

The valve is fitted with a tail which includes a cylindrical housing inwhich the upper end of the semicapillary tube is engaged, the outersurface of which bears against the inner surface of the housing.

BRIEF DESCRIPTION OF THE DRAWING

The invention consists, apart from the arrangements explainedhereinabove, in a certain number of other arrangements which will bedealt with more explicity hereinbelow with regard to embodimentsdescribed with reference to the attached drawing which is, however, inno way limiting.

FIG. 1 of this drawing is a view in vertical section of an aerosoldevice according to a first embodiment of the invention, representedduring dispensing.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 of the drawing, an aerosol device D can be seen fordispensing a composition C with relatively high viscosity. Thecomposition C consists, in particular, of a self-foaming shaving gel orof a thickened emulsion.

The viscosity of the composition C, measured on a Brookfield DV IIIviscometer, needle No. 7, lies in the range of 4000 to 10,000millipascal.second, preferably of 6000 to 8000 millipascal.second,measured at a speed of 100 revolutions/minute and of 30,000 to 150,000millipascal.second, preferably of 50,000 to 120,000 millipascal.second,measured at a speed of 2.5 revolutions/minute.

The device D comprises a can 1 intended to be used with the head 2upwards. The can 1 contains the composition and a gaseous propellantagent B which acts directly on the composition C. In other words, nophysical separation is provided between the gaseous propellant agent Band the composition C. The propellant agent advantageously consists of apressurized gas belonging to the group formed by: air, nitrogen, or aliquefiable propellant which is highly insoluble in the composition,such as 2-H-heptafluoropropane, more widely known by the classificationHCFC 227. Use of a liquefied gas capable of dissolving in thecomposition is avoided.

The head 2 of the can 1 has a frustoconical shape and is provided, atits upper end, with an opening 3 having a rolled edge. A valve collar 4is crimped onto the edge of this opening and a dispensing valve is fixedto the center of the collar 4. The valve 5 comprises a valve body 6around which the central part of the collar 4 is crimped.

An elastic sealing washer 7 is clamped between the front end of thevalve body 6 and a rim of the central part of the collar 4. A rod 8 canslide axially in the valve body 6, this rod projecting outwards. The rod8 includes a central channel 9 emerging upwards, the inner end of whichis axially closed; this channel 9 communicates through radial passages9a (or valve orifices) with a peripheral groove 10. The circular inneredge of the washer 7 is engaged in this groove 10. When the rod 8 is notpushed in, the washer 7 closes the radially directed passage or passages9a and isolates the inside of the can 1 from the channel 9. On the otherhand, when the rod 8 is pushed in, the washer 7 bends in its centralpart and allows communication between the inside of the can 1 and thechannel 9, as shown in FIG. 1.

The rod 8 is returned upwards into the closure position by a coil spring11 arranged between the bottom of the housing provided in the body 6 andthe rod 8. There is a push button 12 equipped with a dispensing nozzle13 on top of the upper end of the rod 8.

At its lower part, the valve body 6 is extended downwards by a valvetail 14, inside which a cylindrical housing 15 is provided, this housingbeing limited, towards the top, by an inner radial shoulder 16. An axialpassage 17 of relatively large diameter, in particular greater than 1mm, connects the housing 15 with the chamber in which the rod 8 canmove.

A semi-capillary dip-tube 18 is engaged by its upper end in the housing15 and extends downwards as far as the vicinity of the bottom 19 of thecan 1.

The internal diameter e of the tube 18 lies between 0.7 mm and 1.5 mmand preferably between 1.3 and 1.5 mm. This cross-section of reduceddiameter lies upstream of the valve orifices 9a.

Surprisingly, with compositions whose viscosity (measured on aBrookfield DV III viscometer, needle no. 7) lies within the followingrange: from 4000 to 10,000 millipascal.second, preferably from 6000 to8000 millipascal.second, at a speed of 100 revolutions/minute and from30,000 to 150,000 millipascal.second, preferably 50,000 to 120,000millipascal.second, at a speed of 2.5 revolutions/minute, the dispenserdevice equipped with a semi-capillary tube 18 allows, by pressing on thepush button 12, as illustrated in FIG. 1, even dispensing of the productthrough the nozzle 13, and reduced losses of gaseous propellant agent.

The emptying ratio obtained during continuous dispensing, in certaincases, may be greater than 80%. The emptying ratio which is obtainedwith the same type of valve, but with a normal dip-tube whose internaldiameter is markedly greater than 1.5 mm, may be lower in absolute termsby 10 points (ratio of approximately 70%).

The pressure of the propellant agent at the start of the spraying, inthe case of a compressed gas, generally lies between 5 and 10 bar, thispressure being preferably equal to 7 bar. In the case of2-H-heptafluoropropane (liquefied propellant agent), the pressure isapproximately 3.5 bar.

With the device of the invention, and the viscosity ranges indicatedhereinabove, the initial delivery rate of the composition lies between 1g/s and 6.5 g/s, preferably between 2 g/s and 4 g/s, inclusive of theend points.

The final composition delivery rate, at approximately 80% emptying,remains greater than 1 g/s.

Tests on the dispensing of a composition with relatively high viscosityas defined previously, with the device of the invention, made itpossible to release a correct product and with a satisfactory emptyingratio, despite high viscosity variations observed as a function of thespeed.

I claim:
 1. Aerosol device for dispensing a composition with relativelyhigh viscosity, in particular a gel or an emulsion, comprising a canintended to be used with the head upwards, containing the compositionand a pressurized gaseous propellant agent acting directly on thecomposition, a dispensing valve being placed at the upper part of thecan on an opening of this can, while a dip-tube connected to the valveextends as far as the vicinity of the bottom of the can, characterizedin that the composition (C) to be dispensed has a viscosity (measured ona Brookfield DV III viscometer, needle no. 7) lying in the range of 4000to 10,000 millipascal.second, preferably of 6000 to 8000millipascal.second, for a speed of 100 revolutions/minute and of 30,000to 150,000 millipascal.second, preferably of 50,000 to 120,000millipascal.second, for a speed of 2.5 revolutions/minute, and in thatthe dip-tube consists of a semi-capillary tube (18) whose internaldiameter (e) lies between 0.7 and 1.5 mm.
 2. Device according to claim1, characterized in that the internal diameter of the semi-capillarytube (18) lies between 1.3 and 1.5 mm.
 3. Device according to claim 1 or2, characterized in that the valve (5) is fitted with a tail (14) whichincludes a cylindrical housing (15) in which the upper end of thecapillary tube (18) is engaged, the outer surface of which bears againstthe inner surface of the housing (15).
 4. Device according to claim 1,characterized in that its emptying ratio is at least 80%.
 5. Deviceaccording to claim 1, characterized in that the pressure of thepropellant agent in the case of a compressed gas lies between 5 and 10bar, while in the case of the propellant agent being liquid-phase2-H-heptafluoropropane, the pressure is approximately 3.5 bar, and inthat the initial composition delivery rate lies between 1 g/s and 6.5g/s.